In streaming fiber suspensions, e.g. suspensions of pulp for paper production low electrical charges are developed. It is of great importance for the efficiency for the paper production as well as for the efficiency of the sewage system that this streaming potential can be measured and controlled continuously.
U.S. Pat. No. 4,687,986 describes a method for continuously measuring the streaming potential in an industrial process. The measurement is carried out across a screen, which removes the fibers in the sample by filtration and the values are processed in a microcomputer.